In order to meet future particulate emission standards for internal combustion (IC) engines, in particular diesel engines, manufacturers of diesel engines are using particulate filters (also referred to as particulate traps). Such particulate filters are typically placed downstream of the turbocharger turbine and remove solid particulate matter before it exits the exhaust system to the ambient environment. After a particulate filter collects particulates for a period of time, increasing the exhaust temperature to a suitable level cleans the filter (also known as regenerating) since the oxygen in the exhaust burns the accumulated carbon in the filter.
Particulate filters for diesel engines are typically relatively large and expensive, and regeneration under light load conditions is problematic because attaining the necessary exhaust temperature is difficult. The use of particulate filters for diesel engines operating under varying load conditions therefore is quite limited. Even when the filter is regenerated, non-combustible ash which accumulates in the filter remains after regeneration, decreasing the efficiency of the filter.
What is needed in the art is a diesel engine which uses a particulate filter to remove solid particulate matter from the exhaust emissions, which effectively removes both combustible and non-combustible particulates from the filter.